1. Field of the Invention
The present invention relates to an apparatus and a method for information processing. Specifically, the present invention relates an information processing apparatus and a method of information processing to be used in such an apparatus, where the apparatus and the method are capable of reducing the memory usage of a wavelet transformation process in the apparatus.
2. Description of the Related Art
Typical image compression systems, which have been used in the art, include JPEG (Joint Photographic Experts Group) and JPEG 2000 standardized by ISO (International Standard Organization).
In recent years, extensive studies have been conducted for a system in which a combination of filters, high-pass filters and low-pass filters, called as a filter bank is employed to divide an image into a plurality of bands and encoding is then performed for every band. In particular, the wavelet encoding, which is free of a matter of block distortion at high compression occurred in DCT (Discrete Cosine Transform), is thought to be promising as a new technology as an alternative to DCT.
JPEG 2000 realizes a great improvement in encoding efficiency compared with JPEG because of employing a combination of the wavelet transform and a high-efficient entropy algorithm (bit modeling in units of bit plane and arithmetic encoding).
The wavelet transform basically includes a process of obtaining input image data and then filtering the image data in both the horizontal direction and the vertical direction to cause hierarchical division of low-path components. In this case, reading/writing operation of data may be performed at high frequency, including reading of image data, writing of a frequency coefficient generated as a result of filtering into memory, re-reading of frequency coefficient, and so on (see, for example, Japanese Published Patent Application No. 2008-022403).